Lightning-arrester.



R. P. CLARK.

LIGHTNING ARRESTER.

APPLICATION FILED JAN. 27, |915.

1,208,484. -Imm@ B90121916 2 SHEETS-SHEET I.

R. P. CLARK.

UGHTNING ARRESTER.

r Amm/Arlon FILED mm1, i915. l' 208,484. Perf-enten Dee. 12,19%.

' 2 SHEETS- SHEET 2.

,if MLN/)N MAMMA/fl Il I . Fmr@ 6 FEF I AMM/WWTF UNITED STATES PATENT OFFICE.

RHODOLPHUS PHILIP CLARK, OF SHELTER ISLAND, NEW YORK.

LIGHTNING-ARRESTER.

appncan'on ined January 27, 1915.

To allwhom t may concern.'

Be it known that I, RHoDoLrHUs IJHrL'n CLARK, a citizen of the United States, and a resident of Shelter Island, in the county of Suffolk and State of New York, have invented certain new and useful Improvements in Lightning-Arresters, of which the following is a specification.

This invention relates to protective discharge devices, known as lightning arresters, surge protectors, etc., and is more particularly concerned with the type of lightning arrester employing electrolytic condenser cells. l"These cells, as is well-known, consist essentially of aluminum electrode plates immersed in a suitable electrolyte. By the passage of current an linsulating film is 'formed on the surface of the electrode plates, and it is on this film that the operation of the cell depends. As long as the normal voltage is maintained the insulating film affords an almost completeU barrier to the passage of current from the line through the discharge path, but in event of a critica-l breakdown voltage being exceeded, the cells no longer constitute an obstruction, but offer a free path for the passage of the high frequency or over-voltage discharges to the ground or from line to line, thereby protecting the apparatus which may be connected with the line, without producing short-circuits or causing other disturbances to the service voltage. If 'the voltage is removed, that is to say if the normal current is cut off, a dissolution of the film in the electrolyte takes place, and, if the cells are left in this condition for a suflicient period, the film will be dissolved to such extent that when thel normal voltage is again applied a heavy current will pass. This is to be avoided, because if the' current should suddenly be restored with the arrester in this condition, the arrester becomes a shortcircuiton the line, thereby destroying itself `and causing delay and possiw ble damage to tlie service. These conditions of -disuse of the' arrester, with consequent dissolution of thellilm and subsequent sudden application of voltage, are particularly likely to occur in connection with arrester-s installed on street cars, which are frequently laid off for repairs. In general, vthe dissolution of the insulating film in these lightning arresters has presented one of the most difficult problems to solve. In the system which I have devised to overcome this diiiiculty, there is inserted in series with the arrester,

. Specification of Letters Patent.

Patented Dec. 12, 1916.

Serial No. 4,616.

before the application of voltage and during the period of film reformation, a resistance, which will limitthe current to a safe value even should the films on the aluminum plates be entirely dissolved at the moment of closing the line switch. Since the current-limiting resistance would not afford a proper discharge path, means are provided whereby the said resistance is short-circuited automatically when the current permitted to pass by the limiting resistance has brought about the normal condition of film insulation in the cells; but the construction is such that the short-circuit is initially open, so that, upon the application of voltage, current can flow through the cells 'only by way of the current-limiting resistance. Vhether through the current-limiting resistance or the short-circuit, the cells are constantly connected with the line circuit; consequently as long as there is voltage on the line the insulating Hlm is maintained. The control of the circuits is effected through a relay, the constitution and relation of which to the other parts of the system may be varied in different specific embodiments, certain of which are illustrated and described.

It is to be understood that the best practice requires that the film on the electrodes of the aluminum Acells be formed in the first instance at the factory, by means of devices arranged for that purpose, and before they are installed in actual operating service with the system which I have devised. My invention can, however, be used to form the insulating films of the aluminum plates for the first time, although it is primarily .designed to reform the films whenever they become partly or completely dissolved after having been once formed. In the drawings forming part hereof: Figures 1, 2, 3 and 4 are diagrammatic representations ofv different forms of the protective device as applied to -direct current work; and Fig. 5 is a diagram illustrating an embodiment of the invention suitable for use with alternating currents.

Reference will first be had to Fig. l. The aluminum cells, of which there are a suitable number connected in series, are designated A, A.` These cells are shunted, as is customary, `by balancing resistances I, to equalize the voltage between the cells. K, K are the main line switches for the arrester. B is the current-limiting resistance,` which is initially in circuit with the condenser cells. E is the armature of a diiferential relay, which is adapted to close the initially separated contacts F. Means is provided whereby the relay is opened and held open when the current is oli'. The particular con-4 struction and arrangement ot' the relay whereby it is held open initially and closed subsequent to the application of voltage may be varied. ln the particular instance shown, the ari'nature lil is an open, loZengge-shaped frame carrying one ol? the contacts F and supported by springl arms c, which are se cured at their inner ends to the armature and fixed at their outer ends to stationary supports. These springs are so arranged as to tend to separate the contacts, and do separate them when nocurrent is passed. ln accordance with the invention the relay is closed only after the limited current permitted to flow through the cells by the resistance B has termed the requisite iilm on the electrodes of the cells, so that there is no longer any danger et 'the arrester becoming a short-circuit on the line if the resistance 'is eliminated. ln the embodiment the invention umili r discussion, the means whereby this result is accomplished comprise d'f 'ferential windings C and D, the winding; (l being connected in series withthe cells and also with the current-limiting resistance l, while the. coil or winding D is included in a circuit al which is in. shunt relation to the cells and also to the resistance B. rlllhe said shunt circuit includes a. regulating,- resistance G. lli/lith the main line switch l, open, and consequently with no voltage on the cells, the condition of the armature li] and the contacts F is as shown, that is, the contacts are open, this condition being maintained by the spring arms e as explained. 1f in the cells the insulating iilms have been more or less dissolved, then when the switches l, l are closed the current will be established in two circuits. ln one circuit it passes through the cells A, A and their balancing resistances l, through the series coil C and the current-limiting resistance B. The other circuit is the shunt circuit al containing the shunt relay coil ll. Since the insulatingV film in the cells is in an untormed condition, a current in excess of the normal value will pass through the first described circuit, This current will cause the series coil C to act on the armature in the direction indicated by the nrrow, that is to say, in the direction tending` to keep the contacts ll` separated. So long,l as the current through the cells It, il, and conse quently through the series coil C, exceeds the normal value, the series coil (l, acting with the sprimgr c, will keep the contacts open, thereby causing the current-limiting resistance B to remain in circuit. Due to the film-forming action of the current in this circuit, however, the current will diminish in value in accordance with the 'formation of the film. I'lhis causes the pull ot the se ries coil U' to diminish in force until such time as its pull, combined with the resistance ol1 the spring; arms e to the closing of' ries coil C plus the opposition which the v springs c oi'l'er to movement ot' the armature l in. the closing1 direction. illani'lfestly, the force oi' 'the spring arms must be less than the force oli 'the shunt coil l), otherwise the shunt coil could not close the contacts when there islittle or no current in the series coil C, The shunt coil l) must have sul'icient force, regulated by the value et the resistance (l and the character of the coil itself, to overpower the springs and the force ot the coil C when the current passing' through the cells il. and the series coil diminishes to the desired normal minimum amount, or at least to an amount which corresponds to a degree ot lilm iforme-tion which will render it safe to short-circuit the resistance l. lWhen the shunt coil of the relay thus asserts itself, a short-circuit is completed around the resistance B through the conductors il, g and the contacts l1". ln Fig. l this shunt also shoitcircuits the series coil C. Under this condition, that is to say with the relay closed, the discharge path includes the cells the conductor f, closed contacts F, und conductor g.

The wiring shown in Fig. '2 difiere from that ot' Fig'. l in that the. conductor f is so arranged that the current-.limiting resistance B, but not the series coil (l is shortcircuited when the relay is closed. lV ith this arrangement a non-iinluctive resistance ll, for which may be substituted the low voltage spark gap ll ot' Fig. 3, is comiected in shunt to the series coil (l, in order to hypass any high frequency discharges which would find dill'iculty in goingthrough the series coil C. The advantage or retaining; the coil (l in series with the cells when thc insulating' film is formed and the shoit-ciicuit closed is that, it any or all oi the aluu'iinum cells should fail while in service, the series coil ot' the relay would he traversed by the increased current, duc to such failure, and the resulting incre." ed pull oi' the coil would cause the short-circuiting contacts to open and thereby insert the currmit-limiting rcsistance B in series with the aluminum cells, thereby reducingN the increased current through the cells and relay to a. salie value.

3 :illustrates a modification ot the lli;

protective device wherein the shunt coil D or' the 'relay is in series with the current-limiting resistance B through a conductor Z forming part of the shuntcircuit d. This connection has the following advantage: When the shunt relay windings and their regulating resistance G are in series with the current-limiting resistance B, the relay coil D can act with the requiredvforce to close the short-circuit only when the voltage across resistance B is a minimum. It will be perceived that at the outset only a light current will pa through the winding D and that this current will increaseas the cells become formed anddiminish the voltage drop across the resistance B, thereby allowing the shunt coil D to absorb moreA power. While the shunt winding increases in power, the series winding exerts a diminishing'pull for the reason explained inl connection with Fig. l.

Fig. 4 illustrates the fact that a relay having a single winding maybe utilized instead of a difet'ential'relay. This system makes use of a connection, such for example as that described in connectionwith Fig. 3, whereby the pull-of the shunt coil D isvariable, increasmg from a minimum, which is inetective to close the rela` armature E against 4the action of suita le mechanical means tending to hold it o en, to a value attained only when the cel s are sufiiciently formed, which closes the relay and thereby completes the short-circuit f2, g2. In'this view there is shown a diiferent pivoted form of armature, and, instead of a spring or springs for, holding the contacts F open when the current is oil', a Weight e is shown as the mechanical equivalent. This weight,l however, or the spring which may be substituted for it, must be of such value relatively to the coil D as to hold the relay open against the pull of this coil until such time as the force exerted by the coilhas increased to a value which corresponds to therequisite condition of film formation in the cells. In other words, the Weight or spring in this instance 'takes the place of both the springs and the series coil in the other forms of the invention. It will be understood that in these other forms, also, the fo ce of gravity may be utilized instead of resilient force for holdin the relay v.open before the application 1o voltage.

It will be'understood that numerous other modifications of the invention may be devised for use iniconncction withdirect current. For example, it will be obvious that the short-circuit, `instead of being opened Wtha ap,fmay be opened by the insertion of a su 'ciently great resistance and closed by 'cutting out such-` resistance. The shunt coil D may be wor 1d or constructed so as to have a large timl -co11stant,-that is, that due to the selfI inductance of the coil windings there is considerable delay between the application of the voltage and the manifestation of the coils greatest force. This permits. of obtaining the desirable eli'ect of allowing more time between the application of voltage on the"cells and the production of the maximum effect of the force tending to close the short-circuit of the current-limiting resistance. Furthermore, it is to be understood that instead of a separate resistance G, the shunt coil may be so constructed as to oti'er suiicient resistance in itself. K The diagram of Fig. 5 illustrates one mode of applying the invention to alternatl ing currents. A, A are the aluminum cells, I2, I2 their balancing resistance/s or inductances. M is the primary of a potential transformer which is connected in series with the current-limiting resistance (or reactance) B2 by the connection m. M is the secondary winding of this potential transformer, which is included in the shunt secondary circuit (Z2 containing the shunt coil D2. A winding N in series with the cells constitutes the primary of a current transformer, or" which P is the secondary `winding contained in the secondary circuit p having the series relay winding C2 therein. The winding N is shunted by a by-pass resistance N for current transmission. The armature E may be as in Figs. 1' to 3, but

carries two movable contacts F2, F3, which coperate with an intermediate fixed contact F4, though manifestly this arrangement of contacts could be reversed. E2 is an oil switch or other suitable switch for shortcircuiting the current-limiting resistance (or reactanee) B2, b2 being the initially open short-circuit- B and S represent, respectively, coils for closing and opening the switch, the circuits r and S of these coils being controlled by thc contacts F2, F8, F* in the manner which will be obvious. T is the battery or source of power for energizing the opening and closing lcoils S and R. U

represents any suitable or known form of vmechanical trip operated by the switch E2 in such fashion that, when the switch is closed, the trip is thrown from the closing Contact V to the opening contact lV, thereby disconnecting the switch-closing coil R from the battery and connecting the opening coil S to the battery. Conversely, when the switch E2 is opened, the trip U is thrown 120 to the closing contact V, thereby disconnecting the switch-opening coil S from the battery and connecting the coil R therewith. A spring Ur is shown in connection with the trip U for completing the movement of this member in either direction after suchmovement has been initiated by the switch E2. Contacts F2 and F3 are, of course, in-

sulatcd from each other.

As far as the connection to ground isconoorinil it will lio iinflorsiooil iA r f loin may he arranged in any i' linoun manner. Figi. l illusiiralenA .l1, al'iw lino gi'rouniloil, hut, olf @mimic3 il. aria ninna-ons other porinislilo :ii-rangonaar when thi i'oziuisil'o conililion oi' iilni 'lorinaf lion hat; 'own attained within i'lwl coll,

il. Yin a lightning arroton lli@ combina* 'lion with an QlQOrolViio coinlrnwi voll, of vuri'inl-liniiling'. rwislanw iniiialljv in 0S u'iih thv cieli. anil a i'iriuit in sliuni' rimaion lo ihn roll anil ini-.lullingl' moans For Short-- viii'uiting;` iaaiil resisi'ancv auionniliiilly when the requisito condition of lilin lfoi'niation lia liiin aainoil within the voll.

l. The coinhination with a lightning; arv rvellor i'vll. of a uuVroni-limilingl riuitanco 'hl'ouglll Whirli tho call is initiallyv uoninf'lioil in ho lino i-ii'ifuil, an iniiiall) oiuln allori@ circuitA ailaploil to conncit thv voll 'with h@ lino,y ainl nioans` including a shunt @ii-nit anil a rola); ior closing' said sli zxii' -.iiit a'lfwr (he insulating film o'iE tha roll has noon foi-inail liv thv curi-ont' passiul through ille cui'i'i\iil,liiiiitiiig rosistanve.

5. ln a piooitivo (lorica. tho Coniliinaiiim of an. Qlei'tl'olytio Condenser coll. a Curroni`- liiniling` rvsistancc initiallyY in serios thorowilli, an initially opin sliox't--cii ,uit in shunt,

rilalion to saiil resistance. a shunt i'ii'cuiL` including a` rogulatinnr rosisianvo anil a 13- laiY voil, anil tho Saiil rola); alapioii lo iiloo saiil shor-ciriuit when, liho riaiuiilie condi lion oi' lilin formation has lawn ai'ainiil. u'ihin iflio coll.

L The ifoinhinal'ion with a Coll ol lilo charm-,lor iloeiirilioil, ol: a uil1'rant-liiniting moans initially in sorios willi 'Elio cell7 an initially open short-circuit in .shunt relation to saiil i-.uz'roniiiniting nwanas` anil moans?, inulinlingj a circuit acting" on a` rr-lajif Afor #losing saiil short-circuit allor l'ho requisito l'ilni has lawn .forinoil in tho roll by the ourront allowed to pass by 'the @umani-limiting nwans.

T. The combination oi' a will after 'i'losorilioiL a Quifronlll anw initially in serios 'l orc oiiiilinv a. rolai 'For aiioinau aiming said. resistance alter n of a i'oqnisiie insulating' lilni in lili@ Cell by lha curi-oni. allowed lo pags hy the Currentliinilingg' means, and means for holdingn Saiil rolay opifn lii'ore he afpplivaiion of voltage.

la'. 'Elio combination oi a oeil ol" the characr-r ilwiii'ioeile ourrvnt-liiniting moans inilially in #siii-ies liorcwiili, means including a. relay for auionialicalljf Slioibcircuii Haiil ruri'onl-lii ing means allor this 'fornaiion o a riiquisito insulaingl lilin in the Coll l1): llio rurroni allowed to i'iasishy tho ciirienliinilingg' moans. and mechanical means :for holilinh said rolayY open liolforo lie applica lion ol voltage.

l). .ln 'a proiifliro devient-lie Combination of an vlmtrolytic condenser cell current-limiting! iniaim'iniially in serios tliirewitln an ini-- iiailiY onen shori-circuii; in Shun?J rla'lion ilo iinl vurz'onl-Ihailing means, a, relay for closin; ssaiil slioriaiiroiiil.means iniliallx7 holding ilio rilay open. anil ilecrioal moans opposed lo lhs. lasbnienionid means incl aapifecl izotl lwvonio oiovlive lo close esaiil relay when a pri-ilvoiininoil Condition oll lni formoiion in lli@ will has holen all'ai'novl.

li). ln a promu-tivo (larice, the combinaliou ol" an olectrolylic condenser cll, cnri'lnifliniiiing ino-ans ini'sialb1 in Series allez-'e- 'illn anii means including' a` diilorenial relay for auomat'cally sliorl-vircuiting Said resistance' when the requisite condition of lilin formation has been attained within the coli.

li. :in :i proiectire device, tho combina- 'lion oi' an olectrolytic condenser cell, om* ront-limiting moans initially in serios therewilh. an iniiiall)y open short-circuit in siinnl; relation lo Saiil Currentlizniling means, a volar Ylor closing said slioiiycircui, moans Afor holding` saiil relay open before ille application ol2 voltage, and diflorenial electrical moans adapted to act upon the relay lo @fleet the closing of the. short-Circuit alter the insulating film of the cell has boon formed by tho cui-ront allowed lo pass by the cnrrcn't-liiniling moans.

l2. ln a proccive (lavica, the combinai'ion of ay roll of lw cliaraolt' floscl'ibeh a i-urronl-liiniting roaisanoo through which tlm will is voniwirl'cil with 'tho line upon ille application oi' voli: f, ay rvlaj for sliorh rirvuiling' said rosih anni), a coil in serios with ih@ sell adapted to holii lli@ relay opon lio' a lime after thol applicaion of voltafgmf and a shun coil ailaneil to overcome the sol-iosa coil lo close ille relay when the roqniail'v roniliiion of film formation has been alainiil within Elio coll. l

12K. ln a protective clovii'i, thccombination of a coll of thv character ilvsriiboil, a

current is oli', a coil acting with said means to hold the relay open for a time after the application of voltage, and a coil acting in the opposite sense and adapted to overcome the other forces in order to close the relay -after the requisite lm has been formed in the cell.

14. In a protective device, the combination of an electrolytic condenser cell, means for limiting the cur 1ent passed through the same upon the application of voltage, means for short-circuiting said current-limiting means upon the formation of a requisite insulating film in the cell, said short-circuiting means comprising a differential relay having coils acting in opposition to each other, the connections being such that the coil tending to open the short-circuit is retained in series with the cells when the current-limiting means is short-circuited.

15. In a protective device, the combination of an electrolytic condenser cell, a current-limiting resistance initially in series with the cell, and means for short-circuiting said current-limiting resistance after the formation of a requisite film in the cell, said means including a relay having a coil tending to close the same to establish the short circuit, rand means connectingy said coil in series with said current-limiting resistance, the relation being such that the force of the said coil is of increasing value as the voltage across the said resistance decreases owing to,thc formation of the insulating film.

1G. In a protective device, the combina- 'tion of an electrolytic condenser cell, a current-limiting resistance initially in series with the cell, and means for short-circuiting said current-limiting resistance after the formation of a requisite film in the cell, said means including a relay, a coil tending to close said relay, Said coil having a regulating resistance connected in series therewith to regulate the current permitted to pass through the coil., means opposing the action of said coil, and means connecting said coil and regulating resistance in series with the current-limiting resistance.

17. In a protective device, the combination -of an electrolytic condenser cell, a current-limiting resistance initially inl series with the cell, and means for short-circuiting said current-limiting resistance comprising a differential relay having opposingr coils, the coil tending to open the relay being in series with the cell and the current-limiting resistance, and the coil tending to close the relay. being in series with the said currentlimiting resistance and in shunt to the cell.

18. In a protective device, the combination of an electrolytic condenser cell, a current-lin'iiting resistance initially in series therewith, means for short-circuiting said ciw-cnt-liniiting resistance comprising a difcurrent-limiting resistance initially in series therewith, an initially open short-circuit in shunt relation to said resistance, .a relay controlling'said short-circuit, means Whereby said relay is-open when current is off, and electrical means connected with the line for closing said'relay and operative to close the relay after the formation ofthe insulating film in the cell.

20. In a protective device, the combination of an electrolytic condenser cell, current-limiting means initially in series therewith, an initially open short-circuit in shunt relation to said current-limiting means, means for holding said short-circuitopen until the cell has been formed by current permitted to pass therethrough by the current-limiting means, and means for ther upon automatically closing the short-circuit.

21. In a. device for plants against excess voltage, and 1n combination, an electrolytic condenser, a resistance in series with said condenser, a shunt circuit in relation to said resistance, contacts in shunt circuit and an electromagnetic device for operating said contacts to close the said shunt circuit dependent upon the requisite condition of film forma-- tion in the condenser.

22. In a device for protecting electric plants against excess voltage, and in combination, a circuit, an electrolytic condenser in said circuit, a resistance also in said circuit, and in series with said condenser, a shunt circuit in relation to said resistance, normally open contacts in said shunt circuit,

and electro-magnetic means for operating said contacts to close and open said shunt circuit dependent upon the condition of film formation in the condenser.

23. In a device for protecting electric protecting .electricplants against excess voltage and in combination, a circuit, an electrolytic condenser in said circuit, a resistance placed across the terminals of said condenser, a resistance also in -said circuit and in series with Said condenser, a shunt circuit in relation to said resistance, normally open contacts in said shunt circuit, and electro-magnetic means for operating said contacts to closeand open said shunt circuit dependent upon the con- 111 1'e111ti1111 130 5:1111 Condeneei, :1.11 eecrcn 1111153111111: 1111111111. the 1'1111 111' which is in the 111111111'y 011111111` 111 511111111111 11 the condenser, 11 Im1111111 111111L111-11111g'11e13i1A device. the C1111 ef 11'111111 1.1.;'111 series with 1111l 811111 121111111111511 :11.111 1'1\ 'i,\t11111fe` :11111 111111111111' 1111111111011 h v the 5:1111011101111-11111g1111'11 11111115115 .'1111' 1f11111'1111111g' {11111:41111111 1'i1'111i1;v 111 11.1111111111 1111111114 111515111111@ 111 11 111111111111' 11111111111111111. 11111111 111e requisite 111111111i1111111111111 1'1'11'11111111111111 1111x 11.111111111111111.:

25. 111 11 1'11111'11 1111 1111111111111@ @lenti-i1: 111111115 11111111151; 0.101% 111113113 111111 in 13111111.11.-- 1111111111. :1 1:11'1'11111. :111 111111111111111' 111111111315111' 111111'1111. :1 1'1s1s1111111x i11 51111115 11'11'11 s:1i11 1:1111- 111 1151 1^i11 s11i111i11:11i1`:1 S111111L1i11c111ti111'e111- 111111 111 y1111 1051511111111. :1 51111111 e11'111i1Av in 111 111111111 111 111i11 11111111111511111111 1111.11'1111111:1g11eti0 11111'11'1. 111ey 1'1111 111? which is 111 111e 51111111 1:11'

@uit in rehltion to the said condenser, an 1.11eet1-o-11111g11eti1; device, the e011 of which is 111 series with the suid'ciieuit of the condenser :11111 resistance. Contacts, 11n armature actuated. by 110th elecro-nmgnetic devices, 11nd a connection 1,1et11'een 511111 armature und Said contacts whereby the Contacts :1re operated. through 'the ;11'11111t111'e te control the shunt 011011111 in relation to the Suid resistance in a 111:11111e1 dependent upon the requisite Condi- 111111 of 111111 formation in said condenser.

In teftinieny whereof I have signed, my 111111115 in 'the presence o two subscribing witnesses.

RHODOLPHS PHILIP CLARK.

fvitnesses L xmm'rm M. LEARY, HENRY H. EARL. 

